Objective To investigate the protective effect of miR-328-3p on oxidized low-density lipoprotein (ox-LDL)-induced coronary artery endothelial cell injury and the potentially relevant mechanisms.

Methods Human coronary artery endothelial cells (HCAECs) were induced with ox-LDL, and the cells were divided into a control group consisting of normal cells, an ox-LDL group receiving ox-LDL treatment, an ox-LDL+miR-NC group transfected with miR-NC and treated with ox-LDL, an ox-LDL+miR-328-3p group transfected with miR-328-3p and treated with ox-LDL, and ox-LDL+miR-328-3p+pcDNA group co-transfected miR-328-3p and pcDNA and treated with ox-LDL, and an ox-LDL+miR-328-3p+insulin-like growth factor 2 (IGF2) group co-transfected miR-328-3p and IGF2 and treated with ox-LDL. The expression level of miR-328-3p was determined with RT-qPCR. Cell proliferation was determined by MTT. Cell apoptosis was measured by flow cytometry. Western blot was conducted to examine the protein expression levels of cleaved cas-3 and IGF2. ELISA was performed to determine the levels of tumor necrosis factor α (TNF-α), interleukin (IL)-6, and IL-1β. Dual luciferase reporter experiment was performed to verify the targeting relationship between miR-328-3p and IGF2.

Results Compared with those of the control group, miR-328-3p expression level and cell activity were significantly reduced in the ox-LDL group (P<0.05), while the apoptotic rate, the protein expression levels of cleaved cas-3, IGF2, Bax, and Bcl-2, and the levels of TNF-α, IL-6, and IL-1β were significantly increased (P<0.05). Compared with those of the ox-LDL+miR-NC group, miR-328-3p expression level and cell activity significantly increased in the ox-LDL+miR-328-3p group (P<0.05), while the apoptosis rate, the protein expression levels of cleaved cas-3 and IGF2, and the levels of TNF-α, IL-6, and IL-1β were significantly reduced. IGF2 was a functional target of miR-328-3p. Compared with those of the ox-LDL+miR-328-3p+pcDNA co-transfection group, the IGF2 protein level was significantly increased (P<0.05) and cell activity was significantly decreased (P<0.05) in the ox-LDL+miR-328-3p+IGF2 co-transfection group, while the apoptosis rate, cleaved cas-3 protein level, and the levels of TNF-α, IL-6, and IL-1β were significantly elevated (P<0.05).

Conclusion miR-328-3p inhibits ox-LDL-induced apoptosis and inflammatory in coronary artery endothelial cell injury through targeted negative regulation of IGF2.